Bean sprouts have been grown and harvested for over 6,000 years. Production has been on a limited scale due to the labor intensive method used. Recently, high production methods have been tried using some of the techniques of hydroponic cultivation. These techniques include the placing of beans in a container, covering the beans with water, and then draining. This method has resulted in poor yeilds since the lowermost beans tend to "drown" and rot. Efforts to prevent "drowning" by periodically stirring the bean sprouts while they are growing have only been partially successful. Stirring the beans causes poor growth because of the tendency of the sprouts to grow downwardly. When they are stirred, some of the beans are pointed upwardly, and the plants must expend much energy in trying to "turn around" resulting in a low yield (i.e., ratio of weight of finished sprouts to beans) and sprouts which are crooked and unhealthy looking.
Lastly, because bacteria grows very rapidly in the dark, moist, and warm conditions in which bean sprouts are grown, spoilage of a few of the "drowned" sprouts frequently results in spoilage of a substantial portion of the sprouts by the time they are ready for harvesting.